1H/19F Magnetic Resonance Molecular Imaging with Perfluorocarbon Nanoparticles

Abstract

Developments in genomics, proteomics, and cell biology are leading a trend toward individualized segmentation and treatment of patients based on early, noninvasive recognition of unique biosignatures. Although developments in molecular imaging have been dominated by nuclear medicine agents in the past, the advent of nanotechnology in the 1990s has led to magnetic resonance (MR) molecular agents that allow detection of sparse biomarkers with a high-resolution imaging modality that can provide both physiological and functional agents. A wide variety of nanoparticulate MR contrast agents have emerged, most of which are superparamagnetic iron oxide-based constructs. However, this chapter focuses on a diagnostic and therapeutic perfluorocarbon (PFC) nanoparticulate platform that is not only effective as a T1-weighted agent, but also supports (19)F MR spectroscopy and imaging. The unique capability of (19)F permits confirmation and segmentation of MR contrast images as well as direct quantification of nanoparticle concentrations within a voxel. PFC nanoparticles have the capability to effectively deliver therapeutic agents to target sites by a novel mechanism termed "contact-facilitated drug delivery." Combined with MR spectroscopy, the concentration of drug delivered to the target site can be determined and the expected response predicted. Moreover, mixtures of nanoparticles with different perfluorocarbon cores can provide a quantitative, multispectral signal, which can be used to simultaneously distinguish the relative concentrations of several important epitopes within a region of interest. In conjunction with rapid improvements in MR imaging, the prospects for personalized medicine and early recognition and treatment of disease have never been better.